This application claims the priority of German patent Application No. 19929455.0-23 filed Jun. 26, 1999, which is incorporated herein by reference.
The invention relates to a door drive, including a diagnostic method, for controlling and adjusting a sliding door. More particularly, the present invention relates to a door drive for a sliding door, which generally comprises an electrically driven motor that operates a rotating lever arm via a gear, and means for detecting the door position by means of a motor control which controls the door speed in dependence on its position, and includes a central data processing unit in which at least one movement profile for the sliding door is stored.
A device for operating a sliding door is known from German Patent 198 28 393 A1. The door drive consists of an electric motor, which opens or closes a sliding door with the aid of a gear and an electromagnetic clutch with belt drive. The sliding door position is determined with a door-position detection device that is not described further herein. Near its two end positions, the sliding door is accelerated or decelerated with a constant gradient. During the start-up, the door is initially accelerated constantly until it reaches a maximum speed and then moves at the same speed until it approaches one of its end positions. Deceleration reduces the door speed near one of its end positions, so that the end position can be reached with as little noise as possible. The door position detection device, which is not shown in further detail here, must then determine whether the end position has been reached, so that the sliding door can be slowed down early enough. Door position detection devices of this type are known from the prior art. They are composed of cam disks or cam plates that are connected to the drive shaft of the door drive and activate different pressure-reaction switches, depending on the respective position of the cam disk. Depending on their position, these switches indicate where the sliding door must at least be located. Six (6) different positions can thus be determined for the sliding door, for example, with 6 pressure-reaction switches. However, a determination of the exact position over the complete moving distance of the sliding door is not possible with pressure-reaction switches of this type.
A door drive of the generic type is disclosed in German Patent 195 40 620 A1. The patent 195 40 620 A1 teaches the monitoring of a door movement by comparing a desired movement profile to an actual movement profile. However, the monitoring in this case is used for generating an interrupt signal for interrupting the movement if the desired movement and the actual movement deviate by a previously specified measure. The predetermined difference value, by which the actual value must deviate from the desired value, only serves to signal the case of an obstacle. The German Patent 195 40 620 A1 discloses that interfering influences on the door movement, caused by soiling or aging of the mechanical parts of the door, are to be taken into account through regular maintenance intervals. The desired movement must be recorded anew time and again because of these maintenance intervals.
Thus, it is the object of the present invention to provide a diagnostic system for automatic sliding doors, with the aid of which deviations from the predetermined movement profile of the sliding door can be detected.
The above object generally is achieved according to the present invention by a door drive for a sliding door comprising: an electrically driven motor that drives a rotating lever arm via a gear, with the lever being coupled to the door for controlling the movement of the door; a transmitting wheel with graduations that is coupled to the lever arm for rotational movement therewith; at least one sensor that cooperates with the transmitting wheel to provide signals corresponding to the angular position of the lever arm, with the output signals of the sensor being fed to a processing unit for detecting the sensor signals to provide an output signal corresponding to a movement profile of the door. A central data processing unit is connected to receive the output signal of the processing unit, and provides output control signals to a control unit for the motor and to an output unit, with at least one desired movement profile for controlling the door operation via the control unit and the motor, and tolerance ranges that indicate the limits within which the measured movement profile for the door operates without problems, being stored in the central data processing unit. The central data processing unit comprises means for adding the stored tolerance ranges to the stored desired movement profile, and for comparing the resulting desired movement profile to the movement profile measured by the sensor (S) and provided by the processing unit, and for providing an error signal to the output unit, to issue an error message if the measured movement profile for the sliding door (B) is outside of the tolerance ranges for the desired movement profile.
Note that the difference value between actual movement and desired movement provided according to the above described prior art reference DE 195 40 620 A1 therefore cannot be compared to the tolerance range utilized according to the present invention. That is, according to the present invention, if the tolerance range is exceeded only an error message is issued. This does not adversely affect the operation of the door. On the other hand, with the door drive according to German patent DE 195 40 620 A1, a soiling or wear of the door will prevent the closing of the door.
According to the present invention, an automatic door is moved with the aid of a lever arm that is operated by a motor and a gear. The end positions of the door, as well as two intermediate positions, are detected with mechanical switches operated by a cam disk. The mechanical switches form a redundant safety system and can, if necessary, be omitted. Independent of the mechanical switches, a non-contacting optical position sensor is used, which consists of a toothed wheel with rectangular gear profile and an optical sensor with transmitter and receiver. For the purpose of detecting the position, the optical position sensor can completely replace the mechanical switches and the cam disk for activating these switches. A toothed wheel with rectangular tooth profile constitutes the transmitting wheel for the optical position sensor. It is possible to reach a conclusion concerning the speed as well as the door position by measuring the distance between the transmitting wheel and the optical position sensor. The rectangular toothed-wheel profile advantageously permits a digital signal evaluation of the optical signals.
Other transmitting wheel designs that are familiar to the person skilled in the art can also be provided. The transmitting wheel is a disk provided with graduations. The graduations can preferably be detected and recognized with the aid of optical devices. Examples for graduations of this type are color markings, mirror coatings, perforated disks, toothed disks, disks with reflective surfaces, disks with reflective prisms and the like.
According to another embodiment according of the invention, the transmitting wheel and the position sensor can be configured as a magnetic sensor system. For that embodiment, the position sensor is a magnetic sensor and the transmitting wheel is provided with magnetically effective graduations, which are known to the person skilled in the art.
The primary advantage achieved with the invention is the simultaneous detection of door position and movement speed of the sliding door, which permits the detection of the complete movement profile of the sliding door. The detected movement profile of the sliding door is compared in a connected data processing system with the predetermined desired movement profile. As a result, it is advantageously possible to recognize the maintenance state of the sliding door without having to carry out a manual inspection.
The larger the fleet of vehicles that must be maintained and serviced by an operator, the higher the advantage of the automatic diagnosis, in particular for sliding doors in trains, street cars or buses.
An exemplary embodiment of the invention is illustrated in the drawings and is explained in detail below.